Portable tamping machine

ABSTRACT

A device for reciprocatingly driving a tamping tool or the like. The tool is hingedly suspended from a bracket by support springs and is biased downwardly by a compression spring. An endless drive belt connects between a lower sheave on the spring support assembly and an upper sheave which is eccentrically driven by a motor. The belt lifts the tool up, and then relaxes, permitting the tool to be forced downwardly by the compression spring and assisted by the support springs. A shiftable guide permits disengagement of the belt from the upper sheave.

United States Patent [72] inventor Herman R. Buck Hartford, Wis.

[21} Appl, No. 5,524

[22] Filed Jan. 26, 1970 [45] Patented Sept. 7, 1971 [73] Assignec M-B-W,1nc. Slinger, Wis.

Continuation-impart of application Ser. No. 759,885, Sept. 16, 1968, now abandoned.

[54] PORTABLE TAMPING MACHINE 4 Claims, 4 Drawing Figs.

{52] 11.8. C1 94/49 [51] Int. Cl EOlc 19/30 [50] Field of Search 94/48, 49

[56] References Cited UNITED STATES PATENTS 1,953,825 4/1934 Finley 94/49 2,098,895 11/1937 Velten 94/49 2,224,506 12/1940 Baily 94/48 2,659,281 11/1953 Lucas 94/49 3,109,354 11/1963 VanKirk 7 94/49 FOREIGN PATENTS 1,091,046 10/1960 Germany 94/48 Primary Examiner.lacob L. Nackenoff AuomeyAndrus, Sceales, Starke & Sawall ABSTRACT: A device for reciprocatingly driving a tamping tool or the like. The tool is hingedl y suspended from a bracket by support springs and is biased downwardly by a compression spring. An endless drive belt connects between a lower sheave on the spring support assembly and an upper sheave which is eccentrically driven by a motor. The belt lifts the tool up, and then relaxes, permitting the tool to be forced downwardly by the compression spring and assisted by the support springs. A shiftable guide permits disengagement of the belt from the upper sheave.

PORTABLE TAMPING MACHINE This application is a continuation-in-part of my copending application Ser. No. 759,885, filed Sept. 16, 1968, entitled PORTABLE TAMPING MACHINE, now abandoned.

BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION The present invention solves the aforementioned problems and improves prior devices by suspending the tamping shoe from its support bracket by resilient spring means, while also providing a compression spring between the shoe and bracket.

In addition, a unique reciprocating drive connection to the shoe is provided, wherein a positive lift of the shoe is followed by a disconnection of the lift mechanism so that the shoe falls downwardly to the surface being tamped, under the force of the spring means and the compression spring. The drive mechanism is thus substantially isolated from the tamping shock.

DESCRIPTION OF THE DRAWING The accompanying drawing illustrates the best mode.

presently contemplated by the inventor for carrying out the invention.

In the drawing:

FIG. 1 is a side elevation of a tamping machine constructed in accordance with the invention with parts broken away and in section:

FIG. 2 is an end elevation generally taken on line 2-2 of FIG. 1;

FIG. 3 is a view of the clutch mechanism taken on line 3-3 of FIG. I; and

FIG. 4 is a fragmentary side elevation of a machine showing a second embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIGS. [-3 of the drawing, the tamping machine comprises a supporting frame or bracket I which is of generally inverted or channel shape having a pair of downwardly extending sides 2 joined by a web 3. In side elevation, bracket I is generally L-shaped with a generally horizontal arm 4 which merges at one end into a generally vertical leg 5.

In accordance with the invention, a generally horizontal, flat tamping shoe tool 6 is suspended from bracket 1. For this purpose, a transverse forward spacer block 7 is secured to the outer surface of leg 5 and suitably supports the ends of a pair of vertically spaced resilient flat springs 8, 9, which are secured to the blocks top and bottom surfaces, respectively. The other ends of springs 8, 9 are secured to the respective top and bottom surfaces of a second transverse spacer block 10. A transverse connector 11 is suitably secured between the rearward portion of tamping tool 6 and the rearward end of the resultant spring assembly, beneath spacer block 10.

An alternative spring assembly provides a resilient energy accumulating pivotal suspension for tool 6 which deflects an gularly and permits reciprocating vertical action of the tool. This second embodiment of tool suspension is shown in FIG. 4, wherein the flat springs are eliminated in favor of an assembly comprising a plurality of elastomeric cylindrical torsion springs 12 mounted on bracket leg 5 and on a connector 13 secured to tool 6. Corresponding pairs of springs on the bracket and connector are joined by arms 14.

Further in accordance with the invention, connector means are provided between bracket arm 4 and tool 6 to continuously bias the tool downwardly. For this purpose, a helical compression spring I5 is secured to bracket arm 4, as by a bol tlike support 16, and the other spring end is biased against a support 17 on tool 6.

Drive means are provided to vertically reciprocate tool 6 to create a tamping action against the ground 18. For this purpose, a suitable motor 19 is mounted to bracket I through a gearbox 20. Motor I9 connects through an output shaft 2], pinion 22, gear 23 and crank shaft 24 to an eccentric'25 on the latter, which is also provided with a counterweight 26. An upper sheave 27 is mounted on eccentric 25 so that, as motor 19 operates, the sheave will rotate eccentrically about the axis of shaft 24.

In addition, a noneccentric lower sheave 28 is mountedona suitable shaft 29 secured to left spacer 10 and is of adifferent 7 bodiment of FIG. 2, the fiat springs are shown in dash lines as deflecting linearly, whereas in the torsion spring embodiment of FIG. 4, the deflection is angular. As soon as sheave 27 begins to move downwardly, belt 30 relaxes or slackens so that the drive is disconnected or disengaged and tool 6 is forced downwardly by the action of the hinged spring support and spring 15. During the downward motion, tool 6 is completely free and unrestrained, relative to belt 30. The reciprocating action then repeats. I

The device thus provides drive means for alternately transmitting lifting force to the tool and automatically disengaging on the downward stroke thereof, which stroke is created by the accumulated energy of the spring supports and of spring IS.

The invention also contemplates prevention of undue wear on belt 30 during continued reciprocating drive. The belt does not rotate in the usual sense, but it does progressively shift incrementally about its sheave supports each time it tightens. This is provided by making the sheaves of different diameters and by making one or both sheaves freely rotatable about their own axes. In the embodiment shown, sheave 27 is fixed as to such rotation, while sheave 28 is rotatably mounted.

It may, at times be desirable to disconnect belt 30 from the drive mechanism. For this purpose, and as best shown in FIG. 3, a U-shaped belt guide 31 is provided with two spaced parallel legs 32 joined by an end member 33. Legs 32 slideably extend through the framework of gearbox 20 so that belt 30 extends through the channel formed by the guide and gearbox.

Means are provided to shift guide 31 to remove belt 30 from upper sheave 27. For this purpose, a crosspiece 34 extends between legs 32, and an operating wire 35 is connected to the crosspiece. Wire 35 extends through a suitable casing 36 to a suitable manually operable lever 37 on the handle 38 of the device. 5

Moving of lever 37 in one direction will cause belt 30 to slide off upper sheave 27 onto a springlike retainer arm 39 mounted eccentrically on the sheave and extending outwardly therefrom. Belt 30 will remain on lower sheave 28 and cannot lift off of it, due to the belt guard 40.

Moving lever 37 in the other direction will reestablish the drive.

While the invention has been described in connection with a tamping tool, the tool head 6 could be replaced by other tools without departing from the spirit of the invention.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

1. A reciprocating tool device comprising, in combination:

a. a bracket,

b. a spring assembly secured at one end to said bracket and adapted for hingelike generally vertical movement,

c. a tool secured to the other end of said spring assembly,

d. a compression spring extending between said bracket and said tool,

e. a drive motor mounted on said bracket,

f. a support connected to the output of said drive motor for eccentric rotation about an axis,

g. an upper sheave mounted on said support,

h. a lower sheave mounted on said spring assembly,

i. and an endless belt mounted on said sheaves so that operation of said motor will cause said belt to alternately lift said tool and then relax to permit said tool to fall free of connection with said belt and under the influence of said compression spring and spring assembly.

The tool device of claim 1 in which:

at least one of said sheaves is rotatable about its own axis, and the sheaves are of different diameters.

A reciprocating tool device comprising, in combination:

a bracket,

a spring assembly secured at one end to said bracket and adapted to hingelike generally vertical movement,

. a tool secured to the other end of said spring assembly;

. a compression spring extending between said bracket and said tool,

e. a drive motor mounted on said bracket,

p awns an upper support connected to the output of said drive motor for eccentric rotation about an axis,

a generally vertically extending flexible belt,

. means mounting said belt on said upper support for eccentric movement therewith,

. and a lower mounting means for said belt, with said lower mounting means being operatively connected to said other end of said spring assembly,

j. the construction being such that operation of said motor will cause said belt to alternatively lift said tool and then relax to permit said too] to fall free of connection with said belt and under the influence of said compression spring and spring assembly.

4. A reciprocating tool device comprising, in combination:

a. a bracket,

. a tool, spring means suspending said tool from said bracket for generally vertical movement thereof, d. a drive motor mounted on said bracket, e. an upper support connected to the output of said drive motor for eccentric rotation about an axis, f. a generally vertically extending flexible belt, g. means mounting said belt on said upper support for eccentric movement therewith, h. and a lower mounting means for said belt, with said lower mounting means being operatively connected to said spring means,

i. the construction being such that operation of said motor 

1. A reciprocating tool device comprising, in combination: a. a bracket, b. a spring assembly secured at one end to said bracket and adapted for hingelike generally vertical movement, c. a tool secured to the other end of said spring assembly, d. a compression spring extending between said bracket and said tool, e. a drive motor mounted on said bracket, f. a support connected to the output of said drive motor for eccentric rotation about an axis, g. an upper sheave mounted on said support, h. a lower sheave mounted on said spring assembly, i. and an endless belt mounted on said sheaves so that operation of said motor will cause said belt to alternately lift said tool and then relax to permit said tool to fall free of connection with said belt and under the influence of said compression spring and spring assembly.
 2. The tool device of claim 1 in which: a. at least one of said sheaves is rotatable about its own axis, b. and the sheaves are of different diameters.
 3. A reciprocating tool device comprising, in combination: a. a bracket, b. a spring assembly secured at one end to said bracket and adapted to hingelike generally vertical movement, c. a tool secured to the other end of said spring assembly; d. a compression spring extending between said bracket and said tool, e. a drive motor mounted on said bracket, f. an upper support connected to the output of said drive motor for eccentric rotation about an axis, g. a generally vertically extending flexible belt, h. means mounting said belt on said upper support for eccentric movement therewith, i. and a lower mounting means for said belt, with said lower mounting means being operatively connected to said other end of said spring assembly, j. the construction being such that operation of said motor will cause said belt to alternatively lift said tool and then relax to permit said tool to fall free of connection with said belt and under the influence of said compression spring and spring assembly.
 4. A reciprocating tool device comprising, in combination: a. a bracket, b. a tool, c. spring means suspending said tool from said bracket for generally vertical movement thereof, d. a drive motor mounted on said bracket, e. an upper support connected to the output of said drive motor for eccentric rotation about an axis, f. a generally vertically extending flexible belt, g. means mounting said belt on said upper support for eccentric movement therewith, h. and a lower mounting means for said belt, with said lower mounting means being operatively connected to said spring means, i. the construction being such that operation of said motor will cause said upper support to alternately lift and lower said belt so that the belt tightens upon said lifting and relaxes upon said lowering to alternately lift said tool and then permit said tool to fall free of connection with said belt. 